What is the plural possessive form of word Mr. Ness?

Here's why:

* Plural: We need to make the word plural because we are talking about more than one Mr. Ness.

* Possessive: We need to show that something belongs to the Mr. Nesses.

Since "Ness" ends in an "s" sound, we add an apostrophe and an "s" to create the possessive form.